The Core provides resources that are either directly shared by two or more projects or that promote project interaction. The PI is responsible for the Core and for assessing how each project interacts with the others. Glutamate clearance and energy metabolism derangement must be put into the context of patient selection, conduct of operative intervention, uniform description of tissue to be studied, and outcome regarding seizure control. The core will, therefore, be divided into four sections: Section 1: Preoperative definition of the patient population and presumed epileptogenic substrate. In this section, the PI will first define the patients that will undergo study, will obtain informed consent, will place electrodes in those patients requiring invasive study, and will make sure that all preoperative and qualitative and quantitative imaging and electrophysiology has been carried out (patient selection at conference, MRI, volumetrics, AVEEG, PET, MRS). Microdialysis assessment of glutamate will be provided both in vivo, when patients undergo invasive study, and in the slice. This data will be used correlatively in all the projects. Section: Intraoperative 13 study and tissue distribution. This involves digitized imaging of the brain intraoperatively to document the site of electrophysiological abnormalities and hippocampus in photographed, sectioned and numbered for investigator review. Section 3: Postoperative tissue characterization. This section is devoted to the neuronal and glial cell counts performed by Dr. Jung Kim which provides the cellular substrate for the metabolic and energy correlation studies. Section 4: Project coordination. The PI will provide coordination and data sharing among the projects assisted by an administrative associate who will maintain weekly conferences, coordinate patient movement among all the preoperative tests including the trips to Brookhaven National Laboratories. The administrator is also responsible for collecting and collating all data, coordinating interdisciplinary studies, and scheduling internal and external advisory meetings.